The primary role of functional matrices in facial growth

The impact of mouth breathing on dentofacial development: A concise review

Mouth breathing is one of the most common deleterious oral habits in children. It often results from upper airway obstruction, making the air enter completely or partially through oral cavity. In addition to nasal obstruction caused by various kinds of nasal diseases, the pathological hypertrophy of adenoids and/or tonsils is often the main etiologic factor of mouth breathing in children. Uncorrected mouth breathing can result in abnormal dental and maxillofacial development and affect the health of dentofacial system. Mouth breathers may present various types of growth patterns and malocclusion, depending on the exact etiology of mouth breathing. Furthermore, breathing through the oral cavity can negatively affect oral health, increasing the risk of caries and periodontal diseases. This review aims to provide a summary of recent publications with regard to the impact of mouth breathing on dentofacial development, describe their consistencies and differences, and briefly discuss potential reasons behind inconsistent findings.

Contribution of Masticatory Muscle Pattern in Craniofacial Morphology: A Systematic Review

Context:

The objective of this systematic review is to analyze the pattern of masticatory muscle and its effects on craniofacial structures.

Method:

Electronic search was conducted for relevant studies in last 20 years (from January 1, 2002 to December 31, 2021) on the following databases: PubMed, Google scholar, Web of Science, Cochrane Library, and Wiley Library database. Hand searching of selected orthodontic journals was also undertaken. The selected studies were assessed for the risk of bias in Cochrane collaboration risk of bias tool. The “traffic plot” and “weighted plot” risk of bias distribution are designed in the RoB 2 tool. Two authors extracted the data which was then analyzed by another reviewer to obtain the final data.

Results:

Six studies fulfilled inclusion criteria. The risk of bias was high for all the studies. The sample size of the studies, methodologies used, muscles under study, parameters of muscles, and statistical analysis performed were extracted. The methodologies and results of the studies were found to be heterogenous.

Conclusions:

It is found that the vertical craniofacial dimensions can be better appreciated by masseter than by medial pterygoid. The volume of masseter is superior predictor than its cross-sectional area. The volume of the medial pterygoid affects the ramus of the mandible and the length and width of the lateral pterygoid are significantly correlated with transverse skeletal dimensions.

An age-related algorithm for management of micro-orbitism from anophthalmia: a systematic review with supplemental case reports

Management of pediatric anophthalmia and resultant micro-orbitism is challenging. The efficacy and safety of treatment methods vary with age as bony changes grow recalcitrant to implants in those at skeletal maturity and osteotomies become technically challenging following frontal sinus pneumatization. This study aims to review methods for managing micro-orbitism and develop an age-based treatment approach. A systematic literature review was conducted. Data were screened and extracted by two investigators and relevant English-language primary-literature was analyzed. Information on sample-size, number of orbits, intervention, age, complications, and prosthetic retention was obtained. Representative case reports are presented, in addition. Nineteen studies met inclusion: 294 orbits in 266 patients were treated. Two studies reported distraction-osteogenesis. Two studies utilized bone grafting. Osteotomies were performed in 41 patients from three studies. Use of solid implants was detailed in two studies. Three studies described osmotic implant. Four studies described inflatable implants. Other techniques were described by three of the included studies, two of which utilized dermis-fat grafting. All but one study were observational case reports or case series. Across all studies regardless of surgical technique, risk of bias and heterogeneity was high due to attrition bias and selective outcomes-reporting. Selection of therapy should be tailored to skeletal-age to optimize outcomes; those 0-4 yrs are managed with dermis-fat grafts, 5-7 yrs managed with implants, and 8+ yrs managed with osteotomies. For those 8+ yrs with aerated frontal sinuses or insufficient bone stock, we propose onlay camouflage prosthetics which improve projection, increase orbital volume, and avoid risk for frontal sinus injury.

Craniofacial treatment protocol for a pediatric patient with obstructive sleep apnea and skeletal Class III malocclusion: A 13-year follow-up

This report aimed to describe the long-term effects of craniofacial growth modification treatment on sleep and breathing functions in a 7-year-old girl diagnosed with skeletal Class III malocclusion and sleep-disordered breathing. Based on the flowchart of orthodontic intervention protocol that we proposed for phenotype-based patient selection and skeletal target-based treatment selection for pediatric patients with sleep-disordered breathing, a 2-phase treatment targeting the nasomaxillary complex was performed. Posttreatment 3-dimensional changes in the skeletal structure and upper airway were evaluated in association with functional assessment using a validated pediatric sleep questionnaire and home sleep test. Esthetic improvement and obstructive sleep apnea cure were achieved without skeletal surgery. The 2-year retention records showed stable occlusion and improved facial profile with normal breathing and sleep.

Application of geometric morphometrics for facial congenital anomaly studies

The face is a small complex three-dimensional (3D) structure composed of various bones and essential organs. Congenital anomalies of those organs represent various deformities; therefore, their quantification has been challenging. Linear measurements, such as lengths or angles between landmarks, called conventional morphometrics, have been used to quantify their phenotypes usually using 2D images, such as photographs or X-ray images. During analysis, geometric information, which refers to the relative position of each structure, is lost. Geometric morphometrics (GM) uses shape configurations, including anatomical landmarks, which can retain geometric information throughout analysis and can help visualize the results, making it tremendously advantageous compared to conventional methods. Morphometric studies investigate variations within groups, identification of group differences, simulation of the ontogeny, or association with specific organs or genetic disorders, and GM can be applied to these purposes using multivariate statistical methods. The calculation of high-dimensional data is usually required and has prevented GM from becoming a major morphometric method. However, recent developments in computer technology and software have enabled us to perform it easily with ordinary home computers, and the number of morphometric studies applying GM for facial congenital anomalies has been increasing recently. In this article, we introduce the concept and application of GM and review previous morphometric studies with GM regarding congenital facial anomalies.

Relationship between Maxillary Sinus Hypoplasia and Maxillary Occlusal Cant: A Cone Beam CT Study

Introduction. Maxillary sinus hypoplasia (MSH) has been reported to cause a cant in the orbital plane. No similar reports exist about the possible impact on the maxilla. The aim of this study was to assess if MSH is associated with maxillary occlusal plane (MOP) cant and if dental or mandibular factors influenced the existence of the MOP cant. Methods. 80 cone beam CT images of subjects with MSH were analyzed for the type of MSH, degree of MOP cant, open or cross bite, mandibular asymmetry, and degenerative joint disease of the temporomandibular joints. The subjects were compared with a control group matched by age and gender. Results. The degree of MOP cant (range 0–5.1°) was not statistically significantly different in unilateral vs. bilateral MSH or between the different types of MSH. The frequency of open bite, crossbite, mandibular asymmetry, or degenerative joint disease in unilateral vs. bilateral MSH or between the different types of MSH was not statistically significantly different. Between the case and control, there was no statistically significant difference in the degree of MOP cant ( $1.3\pm {1.1}^{°}$ vs. $1.1\pm {0.9}^{°}$ , respectively) or frequency of dental and mandibular factors. There was low positive linear correlation between MOP cant and mandibular symmetry in MSH subjects (Spearman’s $\text{rho}=0.23$ ) and controls (Spearman’s $\text{rho}=0.18$ 7). Conclusions. The data suggests a view of the alveolar bone as the adaptable skeletal unit to ensure and bridge the functionality between the nasomaxillary complex and TMJ system–two systems with very different function, and therefore largely independent “matrix units.”

Collum angle of the anterior teeth: A systematic review and meta-analysis

OBJECTIVES

To assess and evaluate the collum angle (CA) of the anterior teeth of the permanent dentition.

METHODS

A search in seven databases for articles that had measured the CA in sagittal malocclusions was conducted until November 30, 2021. The risk of bias was assessed using the Modified Newcastle Ottawa scale. CA measurements using Cone Beam Computed Tomography or lateral cephalograms were included. The CA data were summarized by random-effects inverse generic meta-analyses.

RESULTS

Qualitative analysis of the 17 selected articles revealed that four were rated as "very good," 12 as "good" and 1 as "satisfactory." CA was 4.7° (95% CI of 3.1 to 6.4) and 2.0° (95% CI of 0.1 to 3.9) greater in Class II division 2 and Class III malocclusions respectively, than in Class I malocclusion cases.

CONCLUSION

Majority of the studies were rated as good or very good. Most studies evaluated the CA of the maxillary central incisors in Class II division 2 malocclusion. Studies assessing other maxillary anterior and mandibular anterior teeth are required.

CLINICAL SIGNIFICANCE

Practice of esthetic dentistry for teeth with increased CA is of clinical importance since the angle would determine the longevity and esthetic/cosmetic success of the rehabilitation. Placement of dental implants in areas of missing teeth with increased collum angle leads to excessive stress between the fixture and abutment leading to gingival recession. Thus, knowledge about the collum angle of anterior teeth and its variations in sagittal malocclusions would enable precise treatment planning in the field of esthetic dentistry.

Dental arches in inherited severe isolated growth hormone deficiency

OBJECTIVES

The growth of the dental arches depends on GH and insulin-like growth factor type 1 (IGF1), but the consequences of GH deficiency (GHD) on their growth are still unclear, probably due to the acquired etiology of GHD in most described series, often associated with additional pituitary deficits (thyrotrophic, corticotrophic and gonadotrophic hormones), and imperfections of related replacement therapies, which may affect the dental arch growth. To avoid these limitations, we took advantage of a unique cohort of subjects with isolated GH deficiency (IGHD) due the same mutation in the GH releasing hormone receptor gene, living with very low serum GH and low to undetectable circulating IGF1 levels. Our purpose was to analyze the dimensions of maxillary and mandibular dental arches.

METHODS

22 adult IGHD (15 untreated and 7 previously partially treated with GH) and 33 controls were enrolled in a cross-sectional study using the Ortho Insight 3D and MeshMixer software, RESULTS: In untreated IGHD subjects all maxillary arch measures were smaller than controls, while among mandibular arches, only the mandibular canine width and the mandibular arch length were reduced. In partially GH treated subjects only the palate depth, the maxillary canine width, the maxillary and mandibular arch lengths remained smaller than controls.

CONCLUSIONS

IGHD reduces the growth of maxillary arch to a greater degree than the mandibular arch, suggesting different control of superior and inferior dental arches. GH treatment increases some of these measures.

The Efficacy of a New AMCOP® Elastodontic Protocol for Orthodontic Interceptive Treatment: A Case Series and Literature Overview

BACKGROUND

Elastodontics is a specific interceptive orthodontic treatment that uses removable elastomeric appliances. They are functional appliances that produce neuromuscular, orthopedic and dental effects. Thus, these devices are useful in the developmental age, when skeletal structures are characterized by important plasticity and adaptation capacity, allowing to remove factors responsible for malocclusions. Elastomeric devices are generally well tolerated by patients requiring simple collaboration and management. This work can be useful to update all orthodontists already adopting these appliances or for those who want to approach them for the first time. This study aimed to describe four cases treated with new elastomeric devices called AMCOP Bio-Activators and to provide an overview of elastodontics, its evolution, indications and limits.

METHODS

A total of four clinical cases were presented after a treatment period of 16-20 months to evaluate the clinical and radiological effects of the elastodontic therapy.

RESULTS

The effectiveness of Bio-Activators on clinical cases was evidenced with a significant improvement in skeletal and dentoalveolar relationship, and malocclusion correction in a limited treatment period (16-20 months).

CONCLUSIONS

The Bio-Activators showed clinical effectiveness to achieve therapeutic targets according to a low impact on the patient's compliance.

Maxillary Transverse Deficit: A Retrospective Study of Two Biologically Oriented Devices through a Digital Workflow

The aim of this retrospective study was to compare the efficiency of two biologically oriented devices in achieving maxillary expansion: Rapid Palatal Expander (RPE) and Nitanium Palatal Expander-2 (NPE-2). Thirty-six subjects, divided in two equal groups, were included in this study. Maxillary dental arches were scanned using Trios 3 shape^®, in order to perform a digital analysis of 3D models. The models were analyzed using Autodesk Fusion 360^® and Meshmixer^®. All data obtained from analysis of pre-treatment and post-treatment models were processed using Prism^® software. The anterior arch width, the posterior arch width, the palate height, and palatal surface were measured to evaluate differences between the devices. A D'Agostino-Pearson normality test was done to check the data. A non-parametric t-test was used to compare the anterior and posterior arch width between the two groups, while a parametric t-test was used to compare the palatal height measurements between the two groups. The p-value was calculated. The limit value fixed was 0.05. Palatal width and surface showed a significant increase in both groups, but no significant changes in palatal height were found. The data processed showed that there were no significant differences between the devices (ΔREP-ΔNPE) in variation of anterior arch width, there were no significant differences in variation of posterior arch width and there were no significant differences in variation of palatal height. The comparison between the two groups showed that both methods were equally effective in correcting transverse defect.

Heritability of facial soft tissue growth in mono- and dizygotic twins at 12 and 17 years of age: A retrospective cohort study

OBJECTIVE

The purpose of this investigation of untreated monozygotic and dizygotic twins was to identify the genetic and environmental components to the facial soft tissue growth.

SETTINGS AND SAMPLE POPULATION

The sample consisted of 52 untreated monozygotic twins (36 male and 16 female) and 46 untreated dizygotic twins (23 male and 23 female) from the Forsyth Moorrees Twin Study (1959-1975).

MATERIALS AND METHODS

Lateral cephalograms were taken at 12 and 17 years of age and traced to analyse facial convexity, nasolabial angle, upper and lower lip thickness, upper and lower lip profile and nose prominence. The genetic and environmental components of variance were analysed with structural equation modelling for multilevel mixed-effects model.

RESULTS

At 12 years of age, strong additive genetic influence was seen for facial convexity (70%), upper lip profile (66%) and nose prominence (65%), whereas strong dominant genetic components were found for upper lip thickness (56%). Nevertheless, under unique environment influence were nasolabial angle (58%), lower lip profile (51%) and lower lip thickness (64%). At 17 years of age, only upper lip thickness (55%) and nose prominence (84%) were under strong additive genetic control, while the rest of the variables were under strong dominant genetic control. The only exception was lower lip thickness (61%), which is still influenced by the unique environment.

CONCLUSION

Although monozygotic/dizygotic twins share at least part of their genome, at both times either additive, dominant or environmental components were found. Nevertheless, at 17 years of age most of the variables are either under additive or dominant genetic influence.

Orofacial Muscle Weakening in Facioscapulohumeral Muscular Dystrophy (FSHD) Patients

BACKGROUND

Facioscapulohumeral muscular dystrophy is the third most commonly found type of muscular dystrophy. The aim of this study was to correlate the D4Z4 repeat array fragment size to the orofacial muscle weakening exhibited in a group of patients with a genetically supported diagnosis of FSHD.

METHODS

Molecular genetic analysis was performed for 52 patients (27 female and 25 male) from a group that consisted of 36 patients with autosomal dominant pedigrees and 16 patients with either sporadic or unknown family status. The patients were tested with the southern blotting technique, using EcoRI/Avrll double digestion, and fragments were detected by a p13E-11 telomeric probe. Spearman's correlation was used to compare the fragment size with the degree of muscle weakening found in the forehead, periocular and perioral muscles.

RESULTS

A positive non-significant correlation between the DNA fragment size and severity of muscle weakness was found for the forehead (r = 0.27; p = 0187), the periocular (r = 0.24; p = 0.232) and the left and right perioral (r = 0.29; p = 0.122), (r = 0.32; p = 0.085) muscles.

CONCLUSIONS

Although FSHD patients exhibited a decrease in muscular activity related to the forehead, perioral, and periocular muscles the genotype-phenotype associations confirmed a weak to moderate non-significant correlation between repeat size and the severity of muscle weakness. Orofacial muscle weakening and its association with a D4Z4 contraction alone may not have the significance to serve as a prognostic biomarker, due to the weak to moderate association. Further studies with larger sample sizes are needed to determine the degree of genetic involvement in the facial growth in FSHD patients.

The Association of Tonsil Hypertrophy with Pediatric Dentofacial Development: Evidence from a Cross-Sectional Study of Young Children in Shanghai, China

PURPOSE

The prevalence of dentofacial deformity was reportedly higher than decades ago, to which upper airway (UA) obstruction-induced sleep-disordered breathing (SDB) might contribute a lot. Tonsil hypertrophy appears relatively common in the population of young children. Given that the association between tonsil hypertrophy and pediatric dentofacial deformity remained controversial, this cross-sectional research was designed to explore the internal relationship of those among young children in Shanghai, China.

PATIENTS AND METHODS

A stratified cluster sampling procedure was adopted, and a representative sample of 715 young children (8-10 years old) was recruited. The OSA-18 quality-of-life questionnaires (OSA-18) were finished by their guardians, and well-trained orthodontists performed the oral examinations. After collecting the valuable information, the descriptions and analyses were run by statistical software (SPSS, version 26.0).

RESULTS

715 participants (334 boys and 381 girls) were involved in the analyses. As calculated, the current prevalence of malocclusion identified by Angle's classification was 45.6% in this sample. No evident relation between OSA-18 scores and dentofacial abnormalities (P > 0.05) was found. With the enlargement of tonsil size, the proportion of children with triangular dental arch form (P < 0.05) and high vault palate (P < 0.001) was increasingly higher. More children with protruding profiles and fewer upright profiles were observed as the tonsil size increased, although it did not show a statistical difference (P = 0.103).

CONCLUSION

Dental and craniofacial growth deficiency has become more prevalent among children, demanding more concerns from health authorities. Tonsil hypertrophy plays an essential role in the direction of dentofacial development. More efforts from local health authorities should be made to enhance public propaganda and education on the prevention and interruption of tonsil hypertrophy and related dentofacial abnormalities.

Evaluation of the effects of hypodontia on the morphology of craniofacial structures

OBJECTIVE

The study aimed to investigate the effects of hypodontia on the sagittal and vertical dimensions of the jaws, dentition and the related soft tissue.

MATERIALS AND METHODS

The hypodontia group included 111 patients whose growth was completed with one or more congenitally missing teeth (CMT). Sixty additional patients with skeletal and dental class I relationship, without CMT, and who completed growth, were included as the control group. The hypodontia group was divided into three subgroups according to the intermaxillary (maxillary or mandibular) location, intramaxillary (anterior or posterior) location and the severity of hypodontia (mild: 1-2 CMT or moderate: 3-6 CMT). Twenty-three measurements were performed on lateral cephalograms of the patients. The one-way and Kruskal-Wallis Analysis of Variance tests were used for the statistical analysis. The false discovery-rate analysis was applied for the multiple comparison adjustment.

RESULTS

No significant difference was found in the skeletal measurements between all hypodontia subgroups and the control (P > .05). Upper incisors were found to be retroclined in the anterior hypodontia group. The upper lip was found to be protruded in the mandibulary hypodontia group compared to the control (P < .05).

CONCLUSION

The mild-to-moderate hypodontia did not produce a significant skeletal effect. However, hypodontia can affect the incisors, especially when CMT is in the anterior region. Besides, the effects of severe hypodontia could not be evaluated due to the insufficient number of oligodontia patients.

What does modularity mean?

Modularity is now generally recognized as a fundamental feature of organisms, one that may have profound consequences for evolution. Modularity has recently become a major focus of research in organismal biology across multiple disciplines including genetics, developmental biology, functional morphology, population and evolutionary biology. While the wealth of new data, and also new theory, has provided exciting and novel insights, the concept of modularity has become increasingly ambiguous. That ambiguity is underlain by diverse intuitions about what modularity means, and the ambiguity is not merely about the meaning of the word-the metrics of modularity are measuring different properties and the methods for delimiting modules delimit them by different, sometimes conflicting criteria. The many definitions, metrics and methods can lead to substantial confusion not just about what modularity means as a word but also about what it means for evolution. Here we review various concepts, using graphical depictions of modules. We then review some of the metrics and methods for analyzing modularity at different levels. To place these in theoretical context, we briefly review theories about the origins and evolutionary consequences of modularity. Finally, we show how mismatches between concepts, metrics and methods can produce theoretical confusion, and how potentially illogical interpretations can be made sensible by a better match between definitions, metrics, and methods.

Reduced Tongue Mobility: An Unrecognised Risk Factor of Childhood Obstructive Sleep Apnoea

STUDY OBJECTIVES

Childhood obstructive sleep apnoea (OSA) is an important and prevalent disease. A short lingual frenulum is a risk factor for OSA, but whether tongue mobility also plays a role in OSA aetiology remains unknown. This study aimed to examine tongue mobility in children with and without OSA. We hypothesized that reduced tongue mobility was associated with OSA. We also evaluated the relationship between tongue mobility and craniofacial profile.

METHODS

This was a cross-sectional case-control study. Prepubertal Chinese children aged 5-12 years, suspected to have OSA were recruited from our sleep disorder clinic. All subjects underwent overnight polysomnography (PSG). The lingual frenulum was evaluated based on tongue mobility and free tongue length. Craniofacial measurements were assessed by lateral cephalometry.

RESULTS

Eighty-two subjects (mean age: 8.32 ± 1.70 years, 57 males) were recruited. The mean tongue mobility was 58.2 (±19)% and 67.4 (±15)% (p=0.019) in subjects with and without OSA, respectively. Tongue mobility was inversely correlated with OAHI (r=-0.218, p=0.049). In multivariate logistic regression, low tongue mobility was independently associated with a higher risk of OSA after adjustment for age, sex, BMI z-score, presence of large tonsils and turbinates and nocturnal oral breathing (odds ratio=3.65, 95% CI= 1.22-11.8). Tongue mobility was found to correlate with the cranial base angle (Ba-S-N) (r=0.262, p=0.018), which determines the relative position of the mandible.

CONCLUSIONS

In pre-pubertal children, reduced tongue mobility is associated with the occurrence and severity of OSA. Assessing tongue mobility is recommended in childhood OSA management.

Natural Compounds Attenuate Denervation-Induced Skeletal Muscle Atrophy

The weight of skeletal muscle accounts for approximately 40% of the whole weight in a healthy individual, and the normal metabolism and motor function of the muscle are indispensable for healthy life. In addition, the skeletal muscle of the maxillofacial region plays an important role not only in eating and swallowing, but also in communication, such as facial expressions and conversations. In recent years, skeletal muscle atrophy has received worldwide attention as a serious health problem. However, the mechanism of skeletal muscle atrophy that has been clarified at present is insufficient, and a therapeutic method against skeletal muscle atrophy has not been established. This review provides views on the importance of skeletal muscle in the maxillofacial region and explains the differences between skeletal muscles in the maxillofacial region and other regions. We summarize the findings to change in gene expression in muscle remodeling and emphasize the advantages and disadvantages of denervation-induced skeletal muscle atrophy model. Finally, we discuss the newly discovered beneficial effects of natural compounds on skeletal muscle atrophy.

The role of the nasal region in craniofacial growth: An investigation using path analysis

This study focuses on the role of the nasal region and its interactions with adjacent facial elements during early ontogeny. A series of linear measurements, areas and volumes were extracted from a collection of 227 medical CT-scans of children from 0 to 6 years of age. These measurements describe aspects of the form of the orbit, maxilla, peri-alveolar (subnasal) region, nasal area, eye, oral region, masseter, and temporal muscles. Hypothesized interactions were then examined using path analysis. Two paths were designed: the first to investigate potential interactions in, and relative contributions of the nasal derivatives and adjacent regions to overall facial growth and development; the second path sees the addition of facial soft tissue measurements and aims to assess their effects on skeletal components, and on overall facial growth and development. The results of the first path indicate a large contribution of the nasal and subnasal regions to facial development. This indicates that the nasal septum and the developing dentition provide an important but variable contribution to facial ontogeny during early years. This result is confirmed in the second path, where the soft tissue elements were added to the diagram. Results of the second path indicate that the soft tissues contribute only locally to the development of some skeletal elements of the face. This indicates that the contribution of skeletal components has a more direct effect on facial height than soft tissue matrices, however there are complex interactions between soft tissues and skeletal elements throughout ontogeny.

Structural changes in the trabecular bone of the mandibular condyle of growing patients with sagittal jaw discrepancy treated with the twin-block appliance

OBJECTIVE

The objective of this study was to evaluate the structural changes in the trabecular bone of the mandibular condyles in patients treated with the Twin-block functional orthopaedic appliance that act by promoting condylar growth and to compare the fractal dimension (FD) of condylar trabecular bone structure prior to treatment (T0) and after orthopaedic functional treatment (T1).

SETTING AND SAMPLE POPULATION

This retrospective study included panoramic images of 112 individuals with a mean age of 11.04 ± 1.30 years in the study group (32 girls and 24 boys) and 11.6 ± .80 years in the control group (29 girls and 27 boys).

MATERIALS AND METHODS

The standardized region of interest was selected as the right and left condylar areas close to the articulation surfaces from the twin-block (TB) group, which included patients who completed functional orthopaedic treatment and the control group, which included untreated individuals. FD values in the condylar region were analysed from the panoramic radiographs of both groups using a box-counting method with ImageJ software (version 1.52a, US National Institutes of Health).

RESULTS

There was a significant decrease in the FD values of the right (-.038) and left (-.022) condylar region at T0 and T1 in the TB group. Between-group FD comparisons demonstrated that the TB group showed changes in the condylar region (right, P = .004; left, P = .022) compared to the control group.

CONCLUSION

Functional orthopaedic forces caused a decrease in the trabecular structure of the condylar area examined.

Changes in tongue-palatal contact during swallowing in patients with skeletal mandibular prognathism after orthognathic surgery

This study aimed to evaluate improvement of tongue-palatal contact patterns during swallowing after orthognathic surgery in mandibular prognathism patients. Thirty patients with mandibular prognathism treated by orthognathic surgery (average age of 27 years, 3 months) and 10 controls (average age 29 years, 6 months) participated in this study. Tongue-palatal contact patterns of patients before and three months after surgery were evaluated by electropalatography (EPG) as well as controls. Whole total of tongue-palatal contact at 0.3, 0.2, and 0.1 sec before complete tongue-palatal contact during swallowing were evaluated. The duration of swallowing phases was also examined. Complete contact of tongue-tip in the alveolar part of individual artificial EPG plate were shown at 0.3, 0.2, and 0.1 sec before complete tongue-palatal contact in the controls, although incomplete contact in the alveolar part were shown at 0.3 sec in mandibular prognathism patients. Whole total of tongue-palatal contact at 0.3 and 0.2 sec before complete tongue-palatal contact was significantly lower in the patients before surgery than in the controls (p<0.05). However, these values increased after surgery. The duration of oral and pharyngeal phase was significantly longer in the patients before surgery than in the controls and the patients after surgery (p<0.01). This study demonstrated that the tongue-palatal contact pattern improved and the duration of oral and pharyngeal phase was shortened in mandibular prognathism patients during swallowing after orthognathic surgery. It is suggested that changes in maxillofacial morphology by orthognathic surgery can induce normal tongue movement during swallowing. (The data underlying this study have been uploaded to figshare and are accessible using the following DOI: https://doi.org/10.6084/m9.figshare.14101616.v1).

Genetic and environmental components of vertical growth in mono- and dizygotic twins up to 15-18 years of age

OBJECTIVES

To determine the additive genetic and environmental contributions to the vertical growth of craniofacial structures.

MATERIALS AND METHODS

The sample consisted of 64 untreated monozygotic (44 male, 20 female) and 61 untreated dizygotic twins (32 male, 29 female). Lateral cephalograms taken at 15 and 18 years of age were traced to analyze the sella-nasion-nasal line angle (SN-NL), nasal line-mandibular line angle (ML-NL), sella-nasion-mandibular line angle (SN-ML), sella-nasion-sella-gnathion angle (Y-axis), posterior face height/anterior face height (PFH/AFH), and lower anterior face height/anterior face height (LAFH/AFH). The genetic and environmental components of variance were analyzed with structural equation modeling for multilevel mixed effects.

RESULTS

At 15 years of age, strong dominant genetic control was seen for NL-ML (81%), LAFH/AFH (73%), and Y-axis (57%), whereas strong additive genetic components were found for PFH/AFH (78%), SN-NL (58%), and SN-ML (57%). Unique environmental factors accounted for 18-42% of observed variance, with SN-NL being affected the most (42%). At 18 years of age, only LAFH/AFH (86%) was under strong dominant genetic control, whereas the remainder were under additive genetic influence. The sole exception was SN-NL, which changed from additive to unique environmental influence.

CONCLUSIONS

Either additive or dominant genetic components were found at 15 or 18 years of age for most vertical variables. Environmental factors accounted for about 10-40%, with SN-NL being mostly affected.

Temporomandibular Joint Dysplasia in Cranio-Maxillofacial Dysplasia: A Retrospective Study. Guideline Treatment Proposal

INTRODUCTION

Cranio-Maxillofacial Dysplasias (CMD), including Craniofacial Microsomias, syndromes (such as Treacher Collins or Williams) and isolated Condylo-Mandibulo-Dysplasia, is a controversial subject with treatments as diverse as diagnostic classifications. The authors present here a retrospective study of 85 patients, with congenital condyle dysplasia arising from these 3 main types of CMD, treated with different techniques that aimed to normalize the facial skeleton and occlusion.

METHODS

The authors studied retrospectively 85 patients, aged from 3 to 53 years old, affected by different types of CMD. Treatment options included: costochondral grafts, orthognathic surgeries, distraction osteogenesis procedures, orthodontic and dentofacial orthopedic treatments, and soft tissues surgeries. Outcomes were evaluated by the surgical team.

RESULTS

Seventeen patients were treated with costochondral grafting, 14 with distraction osteogenesis, 17 with orthodontic and dentofacial orthopedic, and 45 with orthognathic surgery. The authors did not perform any nerve grafting or temporomandibular joints prosthesis placement. Fifty-one patients presented an excellent result, 10 a good result, 9 a poor result, 2 a bad result, and 14 an unknown result.

DISCUSSION

Several different treatments of CMD can be proposed. The authors think that major defect in children should undergo costochondral grafting because of its growth potential while in case of minor defect, orthopedic treatment should be tried in the first place. Distraction osteogenesis should be reserved for cases with poor response after orthopedic treatment or growth insufficiency with costochondral grafting. Orthognathic surgery is often necessary at the end of the growth period to obtain an excellent result. Temporomandibular joints prosthesis should be reserved for extreme cases.

Evaluation of mandibular morphologic measurements and trabecular structure among subgroups of impacted mandibular third molars

OBJECTIVE

To investigate mandibular morphologic measurements and trabecular structures that may cause mandibular third molar (MM3) impaction according to MM3 subgroups.

METHODS

A total of 150 MM3 of 2175 panoramic radiographs (PRs) were reviewed. MM3s according to Winter (vertical), Pell & Gregory Class 1 and group: A, B, C on PRs were included in the study group. Fractal dimensions (FD) and mandibular morphologic measurements were evaluated. Statistical analysis for parametric values was performed using one-way analysis of variance (ANOVA). Statistical analysis for non-parametric values was performed using the Kruskal-Wallis H test.

RESULTS

Statistically, a significant difference was found only in terms of angle of impaction among the groups of MM3 (p < 0.05) [Winter (vertical), and Pell & Gregory Class 1 and group A, B, C]. There was no difference among groups A, B, C in mandibular morphology and trabecular structure, but group C showed different characteristics than the other groups only in terms of impaction angle.

CONCLUSION

The trabecular structure and morphometric properties except for the angle of impaction do not affect impacted MM3s with adequate retromolar space and vertical angle.

Association between shape changes and bone remodeling patterns in the middle face during ontogeny in South American populations

The morphology of facial bones is modeled by processes of bone formation and resorption induced by interactions between tissues and compensatory responses. However, the role of remodeling patterns on the morphological changes within and among populations has been scarcely explored. Here, we assess the association between facial shape and the underlying bone cell activity throughout the ontogeny in two Amerindian populations that represent the extremes of craniofacial variation in South America. The sample comprises 71 individuals (36 adults and 35 subadults) representing hunter-gatherers from Patagonia and horticulturists from Northwest Argentina. We analyzed the shape and size of the zygomatic and the maxilla, and compared them with the patterns of bone formation and resorption. Bone formation and resorption were described by quantitative histological analysis of bone surfaces. Morphological changes were described by landmarks and semilandmarks digitized on 3D surfaces obtained from CT images. The results from multivariate statistics analysis show that the patterns of bone remodeling are associated with variation in the morphology of the middle face. We found a similar pattern of facial shape variation along the ontogenetic trajectory in the two samples, and a similar trend in the amount of formation and resorption activities across ages. The main differences between samples were found in the distribution of the areas of bone formation and resorption, possibly associated with mechanical bone response to masticatory loading. These findings provide clues about the processes and mechanisms of bone development involved in the facial morphological differentiation in human populations from southern South America.

Juvenile idiopathic arthritis of the temporomandibular joint - no longer the forgotten joint

Juvenile idiopathic arthritis (JIA) of the temporomandibular joint (TMJ) is common in children, with an increasing awareness of the condition in all healthcare professionals. TMJ involvement presents a challenge in both diagnosis and treatment, as late presentation can still occur as the disease often develops asymptomatically. This can result in facial deformity and/or functional difficulties including obstructive sleep apnoea. Early diagnosis is therefore essential, requiring a high index of clinical suspicion coupled with the judicious use of gadolinium contrast magnetic resonance imaging (MRI). Long-term management is best provided by a multidisciplinary team as patients often need a combination of pharmacological management, surgical interventions, orthodontics, and psychological support. End stage deformity can be treated by different surgical options, each with their own risks and benefits, however recently there is increasing recognition for the role of total alloplastic TMJ replacement. This review focuses on the diagnosis and management of TMJ arthritis and aims to highlight the important role of maxillofacial surgeons in JIA treatment.

A 3D analysis of growth trajectory and integration during early human prenatal facial growth

Significant shape changes in the human facial skeleton occur in the early prenatal period, and understanding this process is critical for studying a myriad of congenital facial anomalies. However, quantifying and visualizing human fetal facial growth has been challenging. Here, we applied quantitative geometric morphometrics (GM) to high-resolution magnetic resonance images of human embryo and fetuses, to comprehensively analyze facial growth. We utilized non-linear growth estimation and GM methods to assess integrated epigenetic growth between masticatory muscles and associated bones. Our results show that the growth trajectory of the human face in the early prenatal period follows a curved line with three flexion points. Significant antero-posterior development occurs early, resulting in a shift from a mandibular prognathic to relatively orthognathic appearance, followed by expansion in the lateral direction. Furthermore, during this time, the development of the zygoma and the mandibular ramus is closely integrated with the masseter muscle.

Influence of botulinum toxin A on craniofacial morphology after injection into the right masseter muscle of dystrophin deficient (mdx-) mice

BACKGROUND

Severe craniofacial and dental abnormalities, typical for patients with progressive Duchenne muscular dystrophy (DMD), are an exellcent demonstration of Melvin L. Moss "functional matrix theory", highlighting the influence of muscle tissue on craniofacial growth and morphology. However, the currently best approved animal model for investigation of this interplay is the mdx-mouse, which offers only a limited time window for research, due to the ability of muscle regeneration, in contrast to the human course of the disease. The aim of this study was to evaluate craniofacial morphology after BTX-A induced muscle paralysis in C57Bl- and mdx-mice, to prove the suitability of BTX-A intervention to inhibit muscle regeneration in mdx-mice and thus, mimicking the human course of the DMD disease.

METHODS

Paralysis of the right masseter muscle was induced in 100 days old C57Bl- and mdx-mice by a single specific intramuscular BTX-A injection. Mice skulls were obtained at 21 days and 42 days after BTX-A injection and 3D radiological evaluation was performed in order to measure various craniofacial dimensions in the sagittal, transversal and vertical plane. Statstical analysis were performed using SigmaStat®Version 3.5. In case of normal distribution, unpaired t-test and otherwise the Mann-Whitney-U test was applied. A statistical significance was given in case of p ≤ 0.05.

RESULTS

In contrast to C57Bl-mice, in mdx-mice, three weeks after BTX-A treatment a significant decrease of skull dimensions was noted in most of the measurements followed by a significant increase at the second investigation period.

CONCLUSIONS

BTX-A can induce changes in craniofacial morphology and presumably partially inhibit muscle regeneration in mdx-mice, but cannot completely intensify craniofacial effects elicited by dystrophy. Further research is necessary in order to fully understand muscle-bone interplay after BTX-A injection into dystrophic muscles.

Anatomical comparison across heads, fore- and hindlimbs in mammals using network models

Animal body parts evolve with variable degrees of integration that nonetheless yield functional adult phenotypes: but, how? The analysis of modularity with Anatomical Network Analysis (AnNA) is used to quantitatively determine phenotypic modules based on the physical connection among anatomical elements, an approach that is valuable to understand developmental and evolutionary constraints. We created anatomical network models of the head, forelimb, and hindlimb of two taxa considered to represent a 'generalized' eutherian (placental: mouse) and metatherian (marsupial: opossum) anatomical configuration and compared them with our species, which has a derived eutherian configuration. In these models, nodes represent anatomical units and links represent their physical connection. Here, we aimed to identify: (1) the commonalities and differences in modularity between species, (2) whether modules present a potential phylogenetic character, and (3) whether modules preferentially reflect either developmental or functional aspects of anatomy, or a mix of both. We predicted differences between networks of metatherian and eutherian mammals that would best be explained by functional constraints, versus by constraints of development and/or phylogeny. The topology of contacts between bones, muscles, and bones + muscles showed that, among all three species, skeletal networks were more similar than musculoskeletal networks. There was no clear indication that humans and mice are more alike when compared to the opossum overall, even though their musculoskeletal and skeletal networks of fore- and hindlimbs are slightly more similar. Differences were greatest among musculoskeletal networks of heads and next of forelimbs, which showed more variation than hindlimbs, supporting previous anatomical studies indicating that in general the configuration of the hindlimbs changes less across evolutionary history. Most observations regarding the anatomical networks seem to be best explained by function, but an exception is the adult opossum ear ossicles. These ear bones might form an independent module because the incus and malleus are involved in forming a functional primary jaw that enables the neonate to attach to the teat, where this newborn will complete its development. Additionally, the human data show a specialized digit 1 module (thumb/big toe) in both limb types, likely the result of functional and evolutionary pressures, as our ape ancestors had highly movable big toes and thumbs.

Cephalometric Analysis of the Craniofacial Morphology in Patients With Moebius Syndrome

BACKGROUND

Patients with Moebius syndrome may present a wide range of associated orofacial malformations, however, their craniofacial morphology has not been established via controlled cephalometric studies.

OBJECTIVE

To present our institution's findings in the cephalometric evaluation in patients with Moebius syndrome.

METHODS

Retrospective, cross-sectional study that included patients with Moebius syndrome over 9 years of age who had lateral cephalometric radiographs. Cephalometric analysis measurements of Ricketts, Steiner, and McNamara were performed. Quantitative data are expressed as mean and standard deviation, and qualitative data are expressed in totals and percentages. Comparative statistics between classic and incomplete Moebius and between patients older and younger than 16 years of age were performed.

RESULTS

Twenty-four patients were included (54.2% females), mean age 17.46 ± 8.85 years. Fifteen patients (62.5%) had classic Moebius syndrome, and nine (37.5%) had incomplete Moebius. Sixty-six percent of the patients presented either micrognathia or retrognathia, 95% showed mandibular hypoplasia, and 75% had a skeletal class II. Maxillary height was increased resulting in a vertical growth pattern. Upper and lower incisors tended towards proclination, and upper and lower lips protruded over cephalometric markings, and a long upper lip was evidenced in 41% of the patients. No significant differences were noted when comparing classic and incomplete Moebius syndrome. Patients younger than 16 years of age had significantly larger sella-nasion-A point and sella-nasion-B point angles, and a higher proportion of skeletal class II cases.

CONCLUSIONS

Patients with Moebius syndrome have a vertical maxillary growth, micro or retrognathia, developing a skeletal class II and lip protrusion.

The effect of rapid maxillary expansion in children: a meta-analysis

INTRODUCTION

Craniofacial growth is modified by chronic mouth breathing. Rapid maxillary expansion leads to separation of the mid-palatal suture, improving the occlusion and the upper airway size.

AIM

Systematically evaluate scientific articles on the effects of rapid maxillary expansion on airway dimensions and classify the quality of the evidence of the information.

METHODS

Searches on PUBMED, LILACS, EMBASE, SCOPUS, WEB OF SCIENCE and COCHRANE, as well as in the grey literature were performed. The articles found were selected and evaluated both for the risk of bias (ROBINS-I) and for the quality of evidence (GRADE).

RESULTS

Of the 309 works found, 26 papers were selected for full reading, of which 22 were excluded. Data compilation and analysis were performed in four papers, two being controlled non-randomized clinical trials and two non-randomized and uncontrolled clinical trials. No randomized clinical trial was found.

CONCLUSIONS

The meta-analysis found an increase in the internasal and inter-zygomatic distances and oropharyngeal volume after rapid maxillary expansion, which, together with clinical findings, makes the recommendation favorable to the intervention. The quality of the evidence for each outcome was considered very low.

Rapid Maxillary Expansion Has a Beneficial Effect on the Ventilation in Children With Nasal Septal Deviation: A Computational Fluid Dynamics Study

Nasal septal deviation (NSD) is one of the most common nasal diseases. Different from common clinical examination methods, computational fluid dynamics (CFD) can provide visual flow information of the nasal cavity. The dimension and volume of the nasal cavity are easily affected by rapid maxillary expansion (RME). The purpose of this study was to use CFD to evaluate the effect of RME on the aerodynamics of the nasal cavity in children with maxillary transverse deficiency and NSD. Computational fluid dynamics was implemented after 3D reconstruction based on the CBCT of 15 children who have completed RME treatment. After treatment, the volume increases in the nasal cavity, nasopharynx, oropharynx, and pharynx were not statistically significant. The wall shear stress of the nasal cavity after RME, 1.749 ± 0.673 Pa, was significantly lower than that before RME, 2.684 ± 0.919 Pa. Meanwhile, the maximal negative pressure in the pharyngeal airway during inspiration was smaller after RME (-31.058 Pa) than before (-48.204 Pa). This study suggests that RME has a beneficial effect on nasal ventilation. The nasal airflow became more symmetrical in the bilateral nasal cavity after RME. Pharyngeal resistance decreased with the reduction in nasal resistance and the increase in the volume of oropharynx after RME.

Pediatric Mandible Reconstruction: Controversies and Considerations

Mandibular reconstruction in pediatric patients has some unique considerations. The method of reconstruction has to factor in the growth potential of the neo-mandible, the native mandible, and the donor site. The condyle is considered the main growth center of the mandible. Current literature indicates that fibula, iliac crest, and scapula osseous flaps do not have the ability to grow. Costochondral grafts exhibit growth because of the costal cartilage component, although the growth is unpredictable. Preservation of the mandibular periosteum can result in spontaneous bone regeneration. Fibula bone harvest in a child mandates close follow-up till skeletal maturity, to monitor for ankle instability and valgus deformity. Dental rehabilitation maintains occlusal relationships, which promotes normal maxillary development. Elective hardware removal should be considered to facilitate future dental implant placement and possible revision procedures. After completion of growth, if occlusion or symmetry is not satisfactory, secondary procedures can be performed, including distraction osteogenesis, orthognathic-type bone sliding operations, and segmental ostectomy.

Effect of functional appliances on the airway in Class II malocclusions

The proximity of the orofacial structures to the upper airway has led to enormous interest in their influence on the airway maintenance mechanism. The recognition of Sleep disorders and the evolution of dental sleep medicine has fueled further interest in the role of orthodontic treatment on the airway particularly in Class II malocclusions. With abundant literature on class II malocclusions and growth modification, it is natural that focus would shift on the effect of functional appliances on the airway. Most studies on the subject show an improvement in the airway in response to functional appliances and these include both two dimensional and three dimensional study of the airway. This review showcases the most significant literature on this field of study against the background of the information that is needed to gauge its clinical relevance.

A Compartment-Based Mathematical Model for Studying Convective Aerosol Transport in Newborns Receiving Nebulized Drugs during Noninvasive Respiratory Support

Nebulization could be a valuable solution to administer drugs to neonates receiving noninvasive respiratory support. Small and irregular tidal volumes and air leaks at the patient interface, which are specific characteristics of this patient population and are primarily responsible for the low doses delivered to the lung (D_DL) found in this application, have not been thoroughly addressed in in vitro and in vivo studies for quantifying D_DL. Therefore, we propose a compartment-based mathematical model able to describe convective aerosol transport mechanisms to complement the existing deposition models. Our model encompasses a mechanical ventilator, a nebulizer, and the patient; the model considers the gas flowing between compartments, including air leaks at the patient–ventilator interface. Aerosol particles are suspended in the gas flow and homogeneously distributed. The impact of breathing pattern variability, volume of the nebulizer, and leaks level on D_DL is assessed in representative conditions. The main finding of this study is that convective mechanisms associated to air leaks and breathing patterns with tidal volumes smaller than the nebulizer dramatically reduce the D_DL (up to 70%). This study provides a possible explanation to the inconsistent results of drug aerosolization in clinical studies and may provide guidance to improve nebulizer design and clinical procedures.

Evaluation Of Dentoalveolar, Skeletal and Soft-Tissue Changes With FFA Including The Multibracket System: A Meta-analysis

Objective: To assess skeletal, dentoalveolar, and soft-tissue effects of fixed functional appliances (FFAs), alone or in combination with multibracket appliances (comprehensive treatment), on Class II malocclusion in postpubertal patients.

Data Sources: Literature survey was conducted using the Medline, SCOPUS, Latin American and Caribbean Health Sciences, and Scientific Electronic Library Online databases and the Cochrane Library, and through a manual search. No restrictions were set regarding the type of fixed appliance, treatment length, or to the cephalometric analysis used. Data extraction was mostly predefined at the protocol stage by 2 authors.

Study Selection: Only double-blind randomized controlled trials (RCTs) of Class II skeletal cases treated by any FFA that had assessed specific skeletal, dental, or soft-tissue parameters were included.

Data Synthesis: A total of 8 articles qualified for the final analysis. The studies were composed of late-adolescent or adult patients who were at the end of their postpubertal growth period. This meta-analysis included data from 271 subjects (142 Class II patients and 129 untreated individuals) and 8 RCTs, which assessed linear as well as angular cephalometric changes induced by Class II treatment with FFAs.

Conclusions: Based on the data available on postpubertal patients, it was concluded that the fixed functional treatment is effective in Class II malocclusion and shows changes in skeletal, dental, as well as soft tissue.

Towards an early 3D-diagnosis of craniofacial asymmetry by computing the accurate midplane: A PCA-based method

BACKGROUND AND OBJECTIVE

Craniofacial asymmetry is a common growth disorder often caused by unilateral chewing. Although an early orthodontic treatment would avoid surgical procedures later in life, the uncertainty of defining the accurate sagittal midplane potentially leads to misdiagnosis and therefore inaccurate orthodontic treatment plans. This novel study aims to 3D-diagnose craniofacial complex malformations in children with unilateral crossbite (UXB) considering a midplane which compensates the asymmetric morphology.

METHODS

The sagittal midplane of 20 children, fifteen of whom exhibited UXB, was computed by a PCA-based method which compensates the asymmetry mirroring the 3D models obtained from cone-beam computed tomography data. Once determined, one side of the data was mirrored using the computed midplane to visualize the malformations on the hard and soft tissues by 3D-computing the distances between both halves. Additionally, 31 skull's landmarks were manually placed in each model to study the principal variation modes and the significant differences in the group of subjects with and without UXB through PCA and Mann-Whitney U test analyses respectively.

RESULTS

Morphological 3D-analysis showed pronounced deformities and aesthetic implications for patients with severe asymmetry (jaw deviation > 0.8 mm) in whole craniofacial system, while initial signs of asymmetry were found indistinctly in the mandible or maxilla. We detected significant (p < 0.05) malformations for example in mandibular ramus length (0.0086), maxillary palate width (0.0481) and condylar head width (0.0408). Craniofacial malformations increased the landmarks' variability in the group of patients with UXB over the control group requiring 8 variation modes more to define 99% of the sample' variability.

CONCLUSIONS

Our findings demonstrated the viability of early diagnosis of craniofacial asymmetry through computing the accurate sagittal midplane which compensates the individual's asymmetrical morphology. Furthermore, this study provides important computational insights into the determination of craniofacial deformities which are caused by UXB, following some empirical findings of previous clinical studies. Hence, this computational approach can be useful for the development of new software in craniofacial surgery or for its use in biomedical research and clinical practice.

Facial morphological characteristics of mouth breathers vs. nasal breathers: A systematic review and meta-analysis of lateral cephalometric data

The present systematic review and meta-analysis was performed to assess the association between mouth breathing and facial morphological characteristics in children and adolescents. PubMed, Medline, Scopus and Google Scholar databases were searched for cross-sectional case-control studies published between 1^st January 1980 and 1^st April 2019. Studies comparing cephalometric data of mouth breathers and nasal breathers were included, while studies on adults were excluded. Meta-analysis was performed regarding 11 angular and 4 linear measurements. A total of 19 studies were included in the systematic review and data from 18 studies were extracted for the meta-analysis. The results indicated statistically significant decreases in Sella-Nasion-Point A (SNA) angle [mean difference (MD)=-1.33; 95% CI -2.03 to -0.63; P=0.0002] and Sella-Nasion-Point B (SNB) angle of mouth breathers as compared to nasal breathers (MD=-1.33; 95% CI -2.18 to -0.49; P=0.002). There was no difference in Point A-Nasion-Point B (ANB) angle between the two groups (MD=0.25; 95% CI -0.26 to 0.75; P=0.34). Mouth breathers demonstrated an increased mandibular plane angle, total and lower anterior facial height and decreased posterior facial height. Within the limitations of the study, the results indicated that mouth breathers tended to have a retrognathic maxilla and mandible, vertical growth pattern with high mandibular plane angle, downward and backward rotation of the mandible and an increase in total and lower anterior facial height and decrease in posterior facial height. Further high-quality studies are required to strengthen the evidence on this subject.

Racial disparity of Crouzon syndrome in maxilla and mandible

The racial disparity of facial features in craniosynostosis patients is not fully understood. The aim of this study was to explore the difference in maxillary and mandibular morphology and spatial position in Asian and Caucasian Crouzon syndrome patients. Ninety-one computed tomography scans were included (12 Asian Crouzon syndrome patients, 22 Asian controls; 16 Caucasian Crouzon syndrome patients, 41 Caucasian controls) and measured using Materialise software. The maxillary and mandibular volumes of Asian patients were both reduced by 19% (P=0.102 and P=0.187), and those of Caucasian patients were reduced by 15% (P=0.142) and 14% (P=0.211) when compared to the respective race-specific controls. Maxilla length of Asian patients was reduced by 6.36mm (14%, P=0.003), while the reduction in Caucasian patients was 4.88mm (10%, P=0.038). ANS was retracted 11.99mm (P<0.001) in Asian patients and 11.54mm (P<0.001) in Caucasian patients. The ANB angle was narrowed by 13.17° (P<0.001) in Asian patients compared to Asian controls, and by 7.02° (P<0.001) in Caucasian patients compared to Caucasian controls. The retrusive midface profiles of Asian and Caucasian Crouzon syndrome look similar; both result from the combined effect of hypoplastic size and backward displacement. However, the insufficiency was found to be more a failure of the anteroposterior maxillary length in Asian patients, and more due to posterior maxillary positioning in Caucasian patients. Therefore, prognathism in Crouzon syndrome patients is more likely caused by displacement rather than elongation of mandibular length in both races. Crouzon syndrome results in the same extent of overall volume deficiency of the maxilla and mandible in these races.

Efficiency evaluation of rapid maxillary expansion treatment on nasal septal deviation using tortuosity ratio from cone-beam computer tomography images

BACKGROUND AND OBJECTIVE

This study aims to assess the effect of Rapid Maxillary Expansion (RME) on Nasal Septal Deviation (NSD) changes from three-dimensional (3D) images.

METHODS

In this study, cone-beam computed tomography (CBCT) images from 15 patients with maxillary constriction (mean age 12 ± 1.6 years) were included. RME treatment with Hyrax appliance was performed in all patients. CBCT scans were taken at three different times; before appliance insertion (T0), after active expansion (T1) and 3 months after appliance insertion (T2). We developed a novel Matlab-based application to quantify NSD based on the tortuosity ratio by dividing the actual length of the septum by the ideal length in the mid-sagittal plane by using this application.

RESULTS

Tortuosity ratio (TR) values were found as 1.03 ± 0.03 (T0), 1.02 ± 0.02 (T1), and 1.02 ± 0.02 (T2). Differences of TR values among these groups were evaluated using the statistical method of ANOVA (ANalysis Of VAriance) for repeated measures with the significance level of p ≤ .05. Results showed significant reductions in TR values between T0-T1 (p ≤ .05) and between T0-T2 (p ≤ .05). Nonetheless, a significant difference between T1-T2 was not determined (p > .05).

CONCLUSIONS

As a result, we can conclude that the NSD degree is affected by the RME treatment. The developed application can be used for both educational and research purposes.

Craniofacial Growth: Current Theories and Influence on Management

Craniofacial development is a highly coordinated process under a tight genetic control and environmental influence. Understanding the core concepts of growth and development of the craniofacial skeleton and the impact of treatment on growth potential is vital to successful patient management. To maximize outcomes and minimize iatrogenic consequences, proper sequencing and timing of interventions are critical. The development of the craniofacial skeleton occurs as a result of a sequence of normal developmental events: brain growth and development, optic pathway development, speech and swallowing development, airway and pharyngeal development, muscle development, and tooth development and eruption.

Relationship between pterygomaxillary fissure morphology and maxillary/mandibular position : A cone beam computed tomography assessment

PURPOSE

The aim of this study was to investigate the possible correlation between maxillary and mandibular positioning via cephalometric analysis with pterygomaxillary fissure (PMF) morphology using cone beam computed tomography (CBCT).

METHODS

In this study, CBCT images from 825 individuals (448 female, 377 male; age range was 18-91 years with this cohort) were analyzed; PMF length and width were measured. Three-dimensional cephalometric analysis was also performed using cephalometric analysis software. The landmarks and measurements in relation to maxillary and mandibular positions were identified and performed for the cephalometric analysis. Analysis of variance (ANOVA) was used for comparison of the parameters, while the Bonferroni test was used for multiple comparisons. Pearson's test was also used to assess the correlations between the parameters.

RESULTS

The results showed that males had significantly larger PMF length (p < 0.001) and width (p < 0.001) compared to females. The mean PMF length was 17.7 mm (standard deviation [SD] 3.2 mm) for right and 17.7 mm (SD 3.3 mm) for left but were not significantly different (p > 0.05). In terms of the cephalometric measurements, a significant correlation was found between upper central incisor (U1toAperp2D) and posterior facial height (PostFaceHtSGo2D) and PMF length, while correlations were found between PMF width and several cephalometric parameters such as lower lip (LwLiptoEPln2D and LwLiptoHLine2D) and occlusal plane (OPtoFHAng2D) (p < 0.05).

CONCLUSION

A significant relationship was observed between PMF morphology and the position of the maxilla or mandible. PMF lengths and widths were larger in males than females. Posteroanterior maxillary and mandibular lengths and posterior facial height are associated with PMF length and width.

Association between snoring and deciduous dental development and soft tissue profile in 3-year-old children

INTRODUCTION

The aim was to study the association between snoring and development of occlusion, maxillary dental arch, and soft tissue profile in children with newly completed deciduous dentition.

METHODS

Thirty-two (18 female, 14 male) parent-reported snorers (snoring ≥3 nights/week) and 19 (14 female, 6 male) nonsnorers were recruited. Breathing preference (nose or mouth) was assessed at the mean age of 27 months by otorhinolaryngologist. At the mean age of 33 months, an orthodontic examination was performed, including sagittal relationship of second deciduous molars, overjet, overbite, and occurrence of crowding and lateral crossbite. Bite index was obtained to measure maxillary dental arch dimensions (intercanine and intermolar width, arch length). A profile photograph was obtained to measure facial convexity.

RESULTS

No significant differences were found between nonsnorers and snorers in any of the studied occlusal characteristics or in measurements of maxillary dental arch dimensions. Snorers were found to have a more convex profile than nonsnorers. Occurrence of mouth breathing was more common among snorers.

CONCLUSIONS

Parent-reported snoring (≥3 nights/week) does not seem to be associated with an adverse effect on the early development of deciduous dentition, but snoring children seem to have more convex profile than nonsnorers. Snoring is a mild sign of sleep-disordered breathing, and in the present study its short time lapse may not have had adequate functional impact on occlusion.

Vertical growth in mono-and dizygotic twins: A longitudinal cephalometric cohort study

OBJECTIVE

The aims of this longitudinal analysis of untreated monozygotic and dizygotic twins were to investigate vertical changes of the craniofacial structures during growth, to determine the concordance between genetically twins and to assess the genetic component for the various aspects of vertical growth.

SETTINGS AND SAMPLE POPULATION

The sample consisted of 34 pairs of untreated monozygotic twins (23 male, 11 female) and 30 untreated dizygotic siblings of multiple birth (8 male, 8 female and 14 mixed) from the Forsyth Moorrees Twin Study (1959-1975); lateral cephalograms taken from 6 to 18 years of age were analysed at 3-year intervals.

MATERIALS AND METHODS

Cephalograms were traced, and longitudinal changes between twins in six angular and proportional vertical cephalometric variables (SN-NL, ML-NL, SN-ML, y-axis, PFH/AFH and LAFH/AFH) were analysed with intraclass correlation coefficients and linear regression modelling.

RESULTS

The concordance between monozygotic/dizygotic twins at 18 years of age was moderate to high with intraclass correlation coefficient values between 0.51 and 0.66. Additionally, sex differences in concordance at 18 years of age were found for three variables. High heritability (66%-79%) was observed for 5 of the 6 variables (LAFH/AFH, ML-NL, y-axis, SN-ML, PFH/AFH), while SN-NL showed limited heritability (34%).

CONCLUSIONS

Although monozygotic/dizygotic twins share at least part of their genetic material, differences in the vertical dimension were found. This supports the complex developmental mechanism of the human face and the varying influence of genetic and environmental factors.